How does the outbreak of 2019-nCoV spread in mainland China? A retrospective analysis of the dynamic transmission routes

Jiang, Xiandeng; Chang, Le; Shi, Yanlin

The fourth outbreak of the Coronaviruses, known as the 2019-nCoV, has occurred in Wuhan city of Hubei province in China in December 2019. We propose a time-varying sparse vector autoregressive (VAR) model to retrospectively analyze and visualize the dyamic transmission routes of this outbreak in mainland China over January 31 - February 19, 2020. Our results demonstrate that the influential inter-province routes from Hubei have become unidentifiable since February 4, whereas the self-transmission in each province was accelerating over February 4-15. From February 16, all routes became less detectable, and no influential transmissions could be identified on February 18 and 19. Such evidence supports the effectiveness of government interventions, including the travel restrictions in Hubei. Implications of our results suggest that in addition to the origin of the outbreak, virus preventions are of crucial importance in provinces with the largest migrant workers percentages (e.g., Jiangxi, Henan and Anhui) to controlling the spread of 2019-nCoV.